Relay for stepwise movement of a toothed member



Aug. 1, 1961 T. M. A. LIPS ETAL 2,994,227

RELAY FOR STEFWISE MOVEMENT OF A TOOTHED MEMBER Filed Feb. 12, 1959 INVENTORS THEODOOR MARIA ALBERT LIPS JACOB VERHOEFF WILHELMUS LAMBBYERTUS VERVEST AGE T 2,994,227 RELAY FOR STEPWISE MOVEMENT OF A TOOTHED MEMBER Theodo or Maria Albert Lips, Jacob Verhoelf, and Wilhelmus Lambertus Vervest, Hilversum, Netherlands, assignors to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed Feb. 12, 1959, Ser. No. 792,894 Claims priority, application Netherlands Feb. 15, 1958 Claims. (Cl. 74-142) The invention relates to a relay intended for moving stepwise a toothed part, this relay comprising a metal core, a coil surrounding this core, an L-shaped yoke secured to the core and an armature secured to the yoke so as to be rotatable and consisting of two limbs, secured to each other approximately at right angles, of which one armature limb extending approximately parallel to the core is loaded by a spring, which may be adjustable.

Such relays are known. The invention consists in that, with such a known relay, the other armature limb has rigidly secured to it one end of a rod made of thin, resilient material whereas the other end of the resilient rod is movable in all directions to a limited extent relative to the limb, this rod causing the member to move. The advantage of the relay according to the invention consists in that the mass of the rod moving the member is small, so that this rod is capable of performing the bilaterally required movements rapidly and without high acceleration forces. Moreover the construction may be compact.

According to one embodiment of the invention the resilient rod is supported near its free end during the operational stroke, whereas it is freely resilient throughout its length during the return stroke. It is therefore not necessary to fix the position of the toothed member during the return stroke.

The limited movability of the resilient rod relative to the limb may be achieved in various ways. In one embodiment of the invention the armature limb has, at the end remote from the point of rotation, a plate which is at right angles to the limb and which has a recess in the form of a trapezium which is preferably rectangular on one side and of which the longer side, which is the base, is at right angles to the side edges of the limb, whereas the free end of the resilient rod projects through the recess and lies, when the relay is out of operation, in a cavity provided at the point where the oblique side and the side opposite the base coincide. This embodiment of the invention is particularly suitable in the case in which the toothed member to be moved is parallel to the longitudinal directon of the relay. If this member is at right angles to the longitudinal direction of the relay a difierent embodiment of the invention is to be preferred; in this case the armature limb is provided on the side of the point of rotation, with a U-shaped plate, of which one side is secured to the armature limb and of which the bridge is at right angles to the armature limb, whereas the other side has a cavity, which lies at the point of intersection between a boundary of the limb at right angles to the side edges and an oblique part, the end of the resilient rod lying in the cavity and projecting beyond the limb, when the relay is out of operation.

According to a further embodiment of the invention provision is made of a stop which is secured rigidly to the relay and which holds the rod in the cavity, when the armature is completely operative. Since the rod is held, the toothed member driven by the rod is also held, so that a possible small motion of the member produced by inertia is avoided.

With a view to the moving force to be exerted by the rod on the member it is desirable that, in accordance with a further embodiment of the invention, when the member to be moved is a pawl wheel, the direction of movement ates Patcnt I Ce 2,994,227

Patented Aug. 1, 1961 FIG. 1 is a side view of a step relay with a pawl wheel to be moved stepwise, and extending parallel to the direction of length of the relay.

FIG. 2 is a side elevation of the arrangement shown in FIG. 1.

FIG. 3 is a side elevation of one of the upper plates of the armature limb, on an enlarged scale.

FIG. 4 is a side elevation of part of a step relay with a pawl wheel to be moved stepwise, the pawl wheel being at right angles to the longitudinal direction of the relay.

FIG. 5 is a plan view of the relay shown in FIG. 4.

FIG. 6 shows, on an enlarged scale, the upper plate of FIG. 4.

Referring to the figures, reference numeral 1 designates a coil comprising a core 2. To the core 2 is secured an L-shaped yoke 3, which is provided with a threaded end 4 to secure the relay. An armature 5, which has two limbs 6 and 7, is pivotally secured to the yoke 3. The limb 6 is loaded by a spring 8, so that this limb is urged against the yoke 3. This spring 8 may be adjustable in known manner, for example by means of a nut.

FIG. 1 and 2 show a pawl wheel 9 with teeth 12, which wheel is secured to a shaft 11 by means of a shoulder 10. The pawl wheel 9 extends parallel to the longitudinal direction of the relay and is to be moved stepwise in the direction of the arrow (FIG. 2) by periodical energization of the relay. The end of the limb 7, remote from the pivot point, is provided with a plate 13, which has a recess 14 shaped in the form of a trapezium with two right angles the longer side of the trapezium, i.e. the base, being at right angles to the side edges of the limb. By means of a block 15 the resilient rod 16 is secured to the limb 7, this rod 16 extends through the recessed plate 13. The rod 16 lies in a cavity 17, when the relay is out of operation, this cavity being provided at the point Where the oblique side and the short side of the trapezium opposite the base coincide. The arrangement of the pawl wheel 9 relative to the rod 16 is such that, when the relay is not energized, the end of the rod lies just outside the circumference of the pawl wheel 9, whereas, when the relay is energized, the resilient rod is urged against one of the radial flat tooth surfaces, the movement being performed approximately along the tangent to the pitch circle. Thus the pawl wheel 9 is turned by one tooth. A stop 18 urges the rod 16 rigidly into the cavity 17 at the end of the operational stroke, so that the pawl wheel 9 is held in place and a further (spontaneous) rotation is not possible. When the relay is deenergn'zed the armature returns into the initial position under the action of the spring 8; the rod, however, which lags slightly owing to inertia is capable of sliding along the oblique tooth surface of the tooth 12, since this rod is now clear of the cavity 17, until it is clear of the oblique tooth surface. The mass of the rod 16 is very small; during the forward movement, while the pawl wheel is turned, the rod is supported near its free end and an adequate force can be exerted on the pawl wheel. When the pawl wheel has turned on the rod is compelled as stated above, by the shape of the tooth, to move aside and since the rod has then a large, free length (during this movement there is no support at the free end) the deviation can be carried out without the need for fixing the position of the pawl wheel; consequently no arrester is necessary, since the force exerted by the rod, during the deviation, 0n the pawl wheel is only very small both owing to the large, resilient length and to the small mass. From the above it will be clear that the size of aperture 14 in plate 13 is suflicient to allow the rod freedom of movement when the limb 7 and plate 13 are returned to inoperative position as seen in the drawings. Thus, the vertical width of the aperture 14 allows the plate 13 to assume inoperative position without engaging the rod and the longitudinal length of the aperture 14 allows the rod to slip past a pawl tooth without engaging the plate 13. Once the rod is free of the pawl wheel 9 the trapezium aperture quickly directs the rod into recess 17 of the aperture 14.

FIGS. 4, 5 and 6 show the pawl wheel 9 at right angles to the longitudinal direction of the relay. The limb 7 of the armature 5 is provided with a U-shaped plate 19, which is rigidly secured to the limb 7, and of which one limb 20 has a cavity 21, which lies at the point of intersection of the limb boundary and an oblique surface. The free end of the spring 16 lies in this cavity, when the relay is out of operation. The operation of the relay as shown in these figures and the advantages of this construction are identical with the operation and the advantages of the embodiments shown in FIGS. 1, 2 and 3, so that we may refer thereto.

In the foregoing reference has been made to a pawl wheel, it will be evident, however, that instead of using a pawl wheel, for example, a toothed rack may be used in which case a translation instead of a rotation takes place. i

From experiments with such a relay and a pawl wheel it was found that at least 25 steps per second can be performed without the need for arresting the pawl wheel.

Since on the one hand no arrester is needed for the pawl wheel to be moved and on the other hand the rod lies beyond the pawl wheel, when the relay is in the rest position, the pawl wheel is free to rotate in the opposite direction. Thus, it is then also possible to mount two pawl wheels with opposite toothing on the same shaft and to use two relays so that the shaft can be moved stepwise in two directions of rotation, which is, of course not well possible, if an arrester is provided and if the rod lies within the circumference of the pawl wheel.

What is claimed is:

1. A relay moving a pawl wheel in a stepwise manner comprising a metal core, a coil surrounding said core, an L-shaped yoke secured to said core, an armature, means pivotally fixing said armataure to said yoke, said armature including two legs located substantially at right angles to one another, spring means biasing one of said legs in a 4 direction toward said core, a thin resilient rod secured at one end to the other of said legs, and means containing the other end of said rod whereby the latter may be moved in all directions to a limited extent, the other end of said rod being adapted to selectively engage one of the teeth of said pawl wheel.

2. A relay moving a pawl wheel in a stepwise manner comprising a metal core, a coil surrounding said core, an L-shaped yoke secured to said core, an armature, means pivotally fixing said armature to said yoke, said armature including two legs located substantially at right angles to one another, spring means biasing one of said legs in a direction toward said core, a thin resilient rod secured at one end to the other of said legs, and a plate secured at the other end of the rod and located substantially perpendicular to said rod, said plate having a trapezoidal opening therein, a recess in said opening, the free end of said rod projecting through said opening and being positioned in said recess when said relay is in the inoperative condition and selectively engaging one of the teeth of said pawl wheel in the operative condition thereof.

3. A relay moving a pawl wheel in a stepwise manner comprising a metal core, a coil surrounding said core, an L-shaped yoke secured to said core, an armature, means pivotally fixing said armature to said yoke, said armature including two legs located substantially at right angles to one another, spring means biasing one of said legs in a direction toward said core, a thin resilient rod secured at one end to the other of said legs, and a U-shaped plate having one leg secured to the other end of said rod and the bight portion extending substantially perpendicularly to said rod, said other leg having a recess therein, the free end of said rod being adapted to selectively engage one of the teeth of said pawl wheel in the operative condition thereof and being positioned in said recess when said relay is in the inoperative condition.

4. A relay as claimed in claim 1 further comprising a stop rigidly secured to said relay which holds said rod when said armature is completely lifted.

5. A relay as claimed in claim 1 wherein the direction of movement of said rod extends approximately along the tangent to the pitch circle of said pawl wheel, and when the relay is in rest position said rod lies spaced from the outer circumference of said pawl wheel.

References Cited in the file of this patent UNITED STATES PATENTS 1,047,810 Hope-Jones Dec. 17, 1912 

